The SITE Intelligence Group which monitors jihadist threats said the graphic was issued Wednesday by the Sunni Shield Media Foundation, which is aligned with the Islamic State.

Video taken by passers-by shows Rogers repeatedly pushing a metal shopping cart toward Shire Ali as he wielded his knife against two policemen trying to subdue him.

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Sydney: Groups aligned with the Islamic state have warned of further attacks on Australia and other Western nations in online posters featuring the deadly lone wolf stabbing rampage in Melbourne last week.

"Australia, don't think you are away from our attacks," read one poster, which showed a photo of a vehicle the Melbourne attacker set alight during his attack last Friday.

The SITE Intelligence Group which monitors jihadist threats said the graphic was issued Wednesday by the Sunni Shield Media Foundation, which is aligned with the Islamic State.

Another graphic posted online and distributed by SITE showed an image drawn from social media showing the Melbourne attacker, Hassan Khalid Shire Ali, trying to stab a policeman before he was fatally shot.

A text overlay on the image says: "Melbourne today - What is the next city tomorrow??!" Shire Ali stabbed and killed one man during the incident and wounded two others before being killed by police.

Australian police characterised the attack as "terrorism" and said the 30-year-old Somali-born Shire Ali was inspired by the Islamic State, but acted alone and had no known ties to the group.

On the day of the attack, Islamic State (IS) said via its propaganda arm that Shire Ali was an "Islamic State fighter and carried out the operation", but provided no evidence to back its claim.

Australia is a member of the US-led coalition that has been fighting IS in Syria and neighbouring Iraq since 2014. The jihadists took large swathes of Syria and Iraq that year, proclaiming a "caliphate" across land it controlled.

But the jihadist group has since lost most of that territory to multiple offensives on both sides of the border.